class AliITSU: public AliDetector

 Default initializer for ITS

     The standard Constructor for the ITS class.

 Default destructor for ITS.

 Creates the AliITSDigitizer in a standard way for use via AliChip.
 This function can not be included in the .h file because of problems
 with the order of inclusion (recursive).
 Inputs:
    AliDigitizationInput *manager  The Manger class for Digitization
 Output:
    none.
 Return:
    A new AliITSRunDigitizer (cast as a AliDigitizer).

 Initializer ITS after it has been built
     This routine initializes the AliITS class. It is intended to be
 called from the Init function in AliITSv?. Besides displaying a banner
 indicating that it has been called it initializes the array fIdSens
 and sets the default segmentation, response, digit and raw cluster
 classes therefore it should be called after a call to CreateGeometry.

 Creates Tree branches for the ITS.
 Inputs:
      Option_t *option    String of Tree types S,D, and/or R.
      const char *file    String of the file name where these branches
                          are to be stored. If blank then these branches
                          are written to the same tree as the Hits were
                          read from.
 Outputs:
      none.
 Return:
      none.

 Creates Tree Branch for the ITS summable digits.
 Inputs:
      cont char *fl  File name where SDigits branch is to be written
                     to. If blank it write the SDigits to the same
                     file in which the Hits were found.

Make branch for digits

 initialize arrays

 Set branch address for the Trees.

 Add an ITS hit
     The function to add information to the AliITSUHit class. See the
 AliITSUHit class for a full description. This function allocates the
 necessary new space for the hit information and passes the variable
 track, and the pointers *vol and *hits to the AliITSUHit constructor
 function.
 Inputs:
      Int_t   track   Track number which produced this hit.
      Int_t   *vol    Array of Integer Hit information. See AliITSUHit.h
      Float_t *hits   Array of Floating Hit information.  see AliITSUHit.h

 fill the chips with the sorted by chip hits; add hits from
 background if option=Add.

 fill the chips with the sorted by chip hits;
 can be called many times to do a merging
 Inputs:
      TTree *treeH  The tree containing the hits to be copied into
                    the chips.
      Int_t mask    The track number mask to indecate which file
                    this hits came from.

 clear accumulated hits

 Standard Hits to summable Digits function.

 Keep galice.root for signal and name differently the file for
 background when add! otherwise the track info for signal will be lost !
 Inputs:
      Int_t evnt       Event to be processed.
      Int_t bgrev      Background Hit tree number.
      Int_t nchips   Not used.
      Option_t *option String indicating if merging hits or not. To
                       merge hits set equal to "Add". Otherwise no
                       background hits are considered.
      Test_t *filename File name containing the background hits..

 Standard Hits to Digits function.

   Keep galice.root for signal and name differently the file for
 background when add! otherwise the track info for signal will be lost !
 Inputs:
      Int_t evnt       Event to be processed.
      Int_t bgrev      Background Hit tree number.
      Option_t *option String indicating if merging hits or not. To
                       merge hits set equal to "Add". Otherwise no
                       background hits are considered.
      Test_t *filename File name containing the background hits..
 Outputs:

 keep galice.root for signal and name differently the file for
 background when add! otherwise the track info for signal will be lost !
 Inputs:
      Int_t evnt       Event to be processed.
      Int_t bgrev      Background Hit tree number.
      Option_t *opt    Option passed to FillChips. See FillChips.
      Test_t *flnm     File name containing the background hits..
 Outputs:
      none.
 Return:
      none.

 RS: TODO
  // This function creates ITS clusters
  if (!IsSimInitDone()) InitSimulation();
  Int_t mmax = 0;
  FillChips(hTree,0);
  //
  TClonesArray *points = new TClonesArray("AliITSRecPoint",1000);
  TBranch *branch=cTree->GetBranch("ITSRecPoints");
  if (!branch) cTree->Branch("ITSRecPoints",&points);
  else branch->SetAddress(&points);
  //
  AliITSsimulationFastPoints sim;
  Int_t ncl=0;
  for (Int_t m=0; m<mmax; m++) {
    sim.CreateFastRecPoints(GetChip(m),m,gRandom,points);
    ncl+=points->GetEntriesFast();
    cTree->Fill();
    points->Clear();
  }
  //
  ClearChips();
  //
  AliDebug(1,Form("Number of found fast clusters : %d",ncl));
  //cTree->Write();
  delete points;

 Tries to find mother's labels

 Reset number of digits and the digits array for the ITS detector.

 Reset number of digits and the digits array for this branch.

 Adds the chip summable digits to the summable digits tree.

    Add a simulated digit.
 Inputs:
      Int_t id        Detector type number.
      AliITSdigit *d  Digit to be added to the Digits Tree. See
                      AliITSdigit.h

 Add a simulated digit to the list.
 Inputs:
      Int_t id        Detector type number.
      Float_t phys    Physics indicator. See AliITSdigits.h
      Int_t *digits   Integer array containing the digits info. See
                      AliITSdigit.h
      Int_t *tracks   Integer array [AliITSdigitS?D::GetNTracks()]
                      containing the track numbers that contributed to
                      this digit.
      Int_t *hits     Integer array [AliITSdigitS?D::GetNTracks()]
                      containing the hit numbers, from AliITSchip, that
                      contributed to this digit.
      Float_t *charge Floating point array of the signals contributed
                      to this digit by each track.

builds ITSgetter (AliLoader type)
if detector wants to use castomized getter, it must overload this method

 This method write FO signals in Digits tree both in Hits2Digits
 or SDigits2Digits

 Standard Summable digits to Digits function.

 Initialize arrays, segmentations ets, needed for simulation
 Equivalent of old AliITSChipTypeSim construction

Standard Classes

Simulation Geometry
 get geometry version - detailed (major) or coarse (minor)

Geometry Transformations

 ITS geometry functions From Simulation

RS  AliITSgeom* GetITSgeom() const {return fChipTypeSim->GetITSgeom();}
RS  void   SetITSgeom(AliITSgeom *geom) {fChipTypeSim->SetITSgeom(geom);}
 return pointer to the array of chips

Hits

sort hits by chip for Digitisation

Fast simulation